KoboFix Font Processor

Overview

kobofix.py is a Python script designed to process TTF and OTF fonts for Kobo e-readers.

It generates a renamed font, fixes PANOSE information based on the filename, adjusts the baseline with the font-line utility, and adds a legacy kern table which allows the kepub engine for improved rendering of kerned pairs.

You can use this to modify or fix your own, legally acquired fonts (assuming you are permitted to do so).

Requirements

Python 3, FontTools, font-line.

You can install them like so:

pip3 install fonttools
pip3 install font-line

On macOS, if you're using the built-in version of Python (via Xcode), you may need to first add a folder to your PATH to make font-line available, like:

echo 'export PATH="$HOME/Library/Python/3.9/bin:$PATH"' >> ~/.zshrc
source ~/.zshrc

Usage

1. Open a terminal and navigate to the directory containing your font files.

2. Run the script with a glob pattern to include all TTF/OTF files:

   python3 kobofix.py *.ttf
   

3. The script will:

   • Validate filenames.
   • Process each font (e.g. "Lora" becomes "KF Lora").
   • Apply kerning, rename, PANOSE adjustments, and baseline shift.
   • Save output as KF_<original_filename>.

Example:

Original: Lora-BoldItalic.ttf
Processed: KF_Lora-BoldItalic.ttf